[PATCH v4 49/59] filename_...xattr(): don't consume filename reference

Al Viro
2026-01-08T07:36:58Z

Callers switched to CLASS(filename_maybe_null) (in fs/xattr.c)
and CLASS(filename_complete_delayed) (in io_uring/xattr.c).

Experimental calling conventions change; with the existing
infrastructure it does not inconvenience the callers, at least
for these ones...

Might be worth doing the same to do_renameat2() and friends.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
fs/xattr.c | 33 ++++++++-------------------------
io_uring/xattr.c | 8 ++++----
2 files changed, 12 insertions(+), 29 deletions(-)

diff --git a/fs/xattr.c b/fs/xattr.c
index 32d445fb60aa..3e49e612e1ba 100644
--- a/fs/xattr.c
+++ b/fs/xattr.c
@@ -649,7 +649,6 @@ int file_setxattr(struct file *f, struct kernel_xattr_ctx *ctx)
return error;
}

-/* unconditionally consumes filename */
int filename_setxattr(int dfd, struct filename *filename,
unsigned int lookup_flags, struct kernel_xattr_ctx *ctx)
{
@@ -659,7 +658,7 @@ int filename_setxattr(int dfd, struct filename *filename,
retry:
error = filename_lookup(dfd, filename, lookup_flags, &path, NULL);
if (error)
- goto out;
+ return error;
error = mnt_want_write(path.mnt);
if (!error) {
error = do_setxattr(mnt_idmap(path.mnt), path.dentry, ctx);
@@ -670,9 +669,6 @@ int filename_setxattr(int dfd, struct filename *filename,
lookup_flags |= LOOKUP_REVAL;
goto retry;
}
-
-out:
- putname(filename);
return error;
}

@@ -688,7 +684,6 @@ static int path_setxattrat(int dfd, const char __user *pathname,
.kname = &kname,
.flags = flags,
};
- struct filename *filename;
unsigned int lookup_flags = 0;
int error;

@@ -702,7 +697,7 @@ static int path_setxattrat(int dfd, const char __user *pathname,
if (error)
return error;

- filename = getname_maybe_null(pathname, at_flags);
+ CLASS(filename_maybe_null, filename)(pathname, at_flags);
if (!filename && dfd >= 0) {
CLASS(fd, f)(dfd);
if (fd_empty(f))
@@ -804,7 +799,6 @@ ssize_t file_getxattr(struct file *f, struct kernel_xattr_ctx *ctx)
return do_getxattr(file_mnt_idmap(f), f->f_path.dentry, ctx);
}

-/* unconditionally consumes filename */
ssize_t filename_getxattr(int dfd, struct filename *filename,
unsigned int lookup_flags, struct kernel_xattr_ctx *ctx)
{
@@ -813,15 +807,13 @@ ssize_t filename_getxattr(int dfd, struct filename *filename,
retry:
error = filename_lookup(dfd, filename, lookup_flags, &path, NULL);
if (error)
- goto out;
+ return error;
error = do_getxattr(mnt_idmap(path.mnt), path.dentry, ctx);
path_put(&path);
if (retry_estale(error, lookup_flags)) {
lookup_flags |= LOOKUP_REVAL;
goto retry;
}
-out:
- putname(filename);
return error;
}

@@ -836,7 +828,6 @@ static ssize_t path_getxattrat(int dfd, const char __user *pathname,
.kname = &kname,
.flags = 0,
};
- struct filename *filename;
ssize_t error;

if ((at_flags & ~(AT_SYMLINK_NOFOLLOW | AT_EMPTY_PATH)) != 0)
@@ -846,7 +837,7 @@ static ssize_t path_getxattrat(int dfd, const char __user *pathname,
if (error)
return error;

- filename = getname_maybe_null(pathname, at_flags);
+ CLASS(filename_maybe_null, filename)(pathname, at_flags);
if (!filename && dfd >= 0) {
CLASS(fd, f)(dfd);
if (fd_empty(f))
@@ -943,7 +934,6 @@ ssize_t file_listxattr(struct file *f, char __user *list, size_t size)
return listxattr(f->f_path.dentry, list, size);
}

-/* unconditionally consumes filename */
static
ssize_t filename_listxattr(int dfd, struct filename *filename,
unsigned int lookup_flags,
@@ -954,15 +944,13 @@ ssize_t filename_listxattr(int dfd, struct filename *filename,
retry:
error = filename_lookup(dfd, filename, lookup_flags, &path, NULL);
if (error)
- goto out;
+ return error;
error = listxattr(path.dentry, list, size);
path_put(&path);
if (retry_estale(error, lookup_flags)) {
lookup_flags |= LOOKUP_REVAL;
goto retry;
}
-out:
- putname(filename);
return error;
}

@@ -970,13 +958,12 @@ static ssize_t path_listxattrat(int dfd, const char __user *pathname,
unsigned int at_flags, char __user *list,
size_t size)
{
- struct filename *filename;
int lookup_flags;

if ((at_flags & ~(AT_SYMLINK_NOFOLLOW | AT_EMPTY_PATH)) != 0)
return -EINVAL;

- filename = getname_maybe_null(pathname, at_flags);
+ CLASS(filename_maybe_null, filename)(pathname, at_flags);
if (!filename) {
CLASS(fd, f)(dfd);
if (fd_empty(f))
@@ -1036,7 +1023,6 @@ static int file_removexattr(struct file *f, struct xattr_name *kname)
return error;
}

-/* unconditionally consumes filename */
static int filename_removexattr(int dfd, struct filename *filename,
unsigned int lookup_flags, struct xattr_name *kname)
{
@@ -1046,7 +1032,7 @@ static int filename_removexattr(int dfd, struct filename *filename,
retry:
error = filename_lookup(dfd, filename, lookup_flags, &path, NULL);
if (error)
- goto out;
+ return error;
error = mnt_want_write(path.mnt);
if (!error) {
error = removexattr(mnt_idmap(path.mnt), path.dentry, kname->name);
@@ -1057,8 +1043,6 @@ static int filename_removexattr(int dfd, struct filename *filename,
lookup_flags |= LOOKUP_REVAL;
goto retry;
}
-out:
- putname(filename);
return error;
}

@@ -1066,7 +1050,6 @@ static int path_removexattrat(int dfd, const char __user *pathname,
unsigned int at_flags, const char __user *name)
{
struct xattr_name kname;
- struct filename *filename;
unsigned int lookup_flags;
int error;

@@ -1077,7 +1060,7 @@ static int path_removexattrat(int dfd, const char __user *pathname,
if (error)
return error;

- filename = getname_maybe_null(pathname, at_flags);
+ CLASS(filename_maybe_null, filename)(pathname, at_flags);
if (!filename) {
CLASS(fd, f)(dfd);
if (fd_empty(f))
diff --git a/io_uring/xattr.c b/io_uring/xattr.c
index 0fb4e5303500..ba2b98cf13f9 100644
--- a/io_uring/xattr.c
+++ b/io_uring/xattr.c
@@ -109,12 +109,12 @@ int io_fgetxattr(struct io_kiocb *req, unsigned int issue_flags)
int io_getxattr(struct io_kiocb *req, unsigned int issue_flags)
{
struct io_xattr *ix = io_kiocb_to_cmd(req, struct io_xattr);
+ CLASS(filename_complete_delayed, name)(&ix->filename);
int ret;

WARN_ON_ONCE(issue_flags & IO_URING_F_NONBLOCK);

- ret = filename_getxattr(AT_FDCWD, complete_getname(&ix->filename),
- LOOKUP_FOLLOW, &ix->ctx);
+ ret = filename_getxattr(AT_FDCWD, name, LOOKUP_FOLLOW, &ix->ctx);
io_xattr_finish(req, ret);
return IOU_COMPLETE;
}
@@ -186,12 +186,12 @@ int io_fsetxattr(struct io_kiocb *req, unsigned int issue_flags)
int io_setxattr(struct io_kiocb *req, unsigned int issue_flags)
{
struct io_xattr *ix = io_kiocb_to_cmd(req, struct io_xattr);
+ CLASS(filename_complete_delayed, name)(&ix->filename);
int ret;

WARN_ON_ONCE(issue_flags & IO_URING_F_NONBLOCK);

- ret = filename_setxattr(AT_FDCWD, complete_getname(&ix->filename),
- LOOKUP_FOLLOW, &ix->ctx);
+ ret = filename_setxattr(AT_FDCWD, name, LOOKUP_FOLLOW, &ix->ctx);
io_xattr_finish(req, ret);
return IOU_COMPLETE;
}
--
2.47.3